Conventionally, an air compressor is mounted as an air source to a vehicle including a truck, in order to feed compressed air to a servo unit or the like of an air brake (refer to, for example, Patent Document 1).
Generally, the air compressor mentioned above is driven by power of an engine of the vehicle, and feeds the compressed air to an air tank at the time of load running. Furthermore, when the compressed air is filled in the air tank, the air compressor is under no load running based on a motion of a governor, and the feed of the compressed air to the air tank is stopped. Accordingly, a consumed horsepower in the air compressor is reduced. Note that a lubrication of the air compressor is carried out by conducting engine oil from the engine.
Patent Document 1: Japanese Unexamined Patent Application Publication No. H08-193576